Manufacture of articles from steel alloys



Patented 10...; 1936 v UNITED STATES 2.05am mmcrscrmsor sancmsmou STEEL.

' .mors I V Frledrieh Karl Naumann, Essen, Germany, asliner .to Fried. .Krupp Aktiengesellschai't,

{ Essen-on-the-Buhr,

No Application November 22, 1933, In Germany December 7,

Serial N0. 699,300.

- 3 Claims. (o1. Ne-123) This invention relates to'the manufacture of articles that by their nature are subjected in use to, and must withstand the attack of, gases that attack and remove carbon, The invention is par- 5 ticularly applicable to-themanufacture of appsratus' and parts thereof whichareused in the destructive hydrogenation ofoil and coal, or in .the synthesis of ammonia, and; with which hydrogen or mixtures of gases containing hydrogen in come into contact at high temperatures and'pressures. It is known to make such apparatus and parts thereof from so-called alloy steels containing chromium,'tungsten, molybdenum, or vanadium, andin somecases nickelalso.

ratus for cracking'.oil and tar tomake use of steel alloys which contain upt'o 13% chromium, and which may-also contain one or more elements as follows:0.3 to- 4% aluminum, 0.2 to 2.5%

20 copper, and up to 2% silicon, molybdenum, vanadium, titanium orberyllium The present in vention is not concerned with the apparatus or parts thereof used in cracking processes but with regard to the treatment of oil andicoal only with apparatus in which 011 and, coal are brought into reaction with hydrogen and the operation is carried on at high hydrogen partial pressures.

According to the present invention use is made for the manufacture of the articles in question of steel alloys which contain titanium and if desired one or more of the elements silicon, manganese, nickel, cobalt, chromium, tungsten. molybdenum and vanadium. It has been found that, titanium possesses to a a much greater degree than chromium, tungsten,

' molybdenum and vanadium, the property of making steel'resistant to the attack of gases that attack and remove carbon, such for instance as the attack of hydrogen at high temperatures and pressures. This greater capacity for resisting hydrogen at high temperatures and pressures is clearly illustrated by the result of the following experiments. I

- Tubes of external dlameterof 30 mm. and internal diameter of 12 mm.were made fromstee alloys ofthe following composition:- asi, 0.50% Mn, 0.0% Cr, 0.4 M6 and 0.50%

1. 0.1mm 024% 81, 0.38% m, 3.18% Cr,

" Hydrogen under a pressure of' 300 atmospheres and at a temperatureof 700 0., was led through these tubes. The tube made from steel, No. l burst after 48 hours, and subsequent examina tion of the tube showed that carponchad been It is also known in the manufacture of appa- Patent leiremoved to a depth of 2 mm. The tube made from steel No. 2 was still undamaged after being tested for 100 hours and showed no loss of carbon. The carbon content of the alloys 'used according to the invention preferably does not exceed 1%.- The titanium content preferablydoes not exceed 5%. It is particizlarly advantageous to make the titanium content at least four times as great as the carbon contentso that the whole of the carbon is bound tothe titanium as titanium carbide: However, if smaller titanium contents are used there is still a substantialincrease in the resistance to hydrogen.

In order. to improve themechanical properties the steel alloys may contain besides titanium one or more ofthe elements silicon, manganese, nickel, cobalt, chromium. tungsten, molybdenum and vanadium, and the total content of these elements may amount to In general, however, atotal content of not more than 15% is found desirable. Even when these additional elements are present the titanium remains theprincipal factor in imparting resistance to loss of carbon, d this is particularly the case when the titanium content is at least four times as great asthe carbon content. I5 1 It has been found particularly suitable to make vuse of steel alloys which contain carbon in an amount not exceeding 0.4%, titanium in an amount not exceeding 2%, and molybdenum'or vanadium or both in a total amount not exceeding 3%, with or without chromium in-an amount not exceeding 10%. For apparatus for' the. destructive hydrogenation of oil and coal as well as for'the synthesis of ammonia the following steel alloys may, for example, be used:-'

1. A. steel alloy containing about 0.15% 0,. 0.23% Si, 0.36% Mn, 0.80% Cr, 0.40% Mo and 0.83% Ti, a 1 40 2. Asteel alloy containing" about 0.10% C,

0.50% Si, 0.40% Mn, 0.130 Cr, 2.2 Moand' 3. A steel alloy containing about 0.10% C,

0.30% Si, 0.40% Mn, 054.0% M0 and 0.50% Ti,

4. A steel alloy containing about 0.10% C,

Y Tj' what I claimand desire to secure by Letters 7 L' 'Artfcles which in their normaluse are sub-1 i'ected to the attack of hytlrogelrat high liydrogen partial pressures and high temperatures, said articles being composed of a steel alloy consisting ofcarbon not over 1%: a small amount of silicon is 2 r 2,oso,aos

' not over about 1.5%; a. small amount of man- 3.,Articles which in their normal use are suhganesenot over about 0.5%.; 'an amount of tijected to the attack of hydrogen nt-high hydrotanium mmcient to protect the carbon, within gen partial pressuresnnd high temperatures, said the range of 0.4-5%; the remainder substanticlh tarticles being composed of a steel alloy consisting 5 iron. of carbon not over 1%; a. small amount or sili- 5 2. Articles which in their normal use are suhcon not over 1.5%; an'amount of titanium sum- Jected to the attack of hydrogen at high hydro- -cient to protect the carbon. within the range oi gen partial pressures and high temperatures, said 0.44%; the remainder suhstlntially iron with a, articles being composed of a. steel alloy consisting manganese content withinthe usual range for 1 .0! shout 0.11% C, 0.33% Bi, 0.5% Mn, 0.46% Ti, low alloy steels.-

5nd remainder substantially KARL HAUMANN. 

